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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
901

Avaliação da poluição sonora e dos teores de BTEX em kartódromos da cidade do Rio de Janeiro / Evaluation of noise polutions and the levels of BTEX in karting circuits in Rio de Janeiro

Lauro de Sena Laurentino 31 March 2010 (has links)
Este trabalho teve como objetivo o monitoramento ambiental incluindo, a avaliação da temperatura ambiente, umidade relativa, ruído e qualidade do ar de kartódromos indoor e outdoor, localizados na cidade do Rio de Janeiro. A qualidade do ar foi monitorada através da determinação dos teores de benzeno, tolueno, etil-benzeno e xilenos, conhecidos como BTEX. Esses compostos apresentam alta toxicidade e se encontrados acima dos limites permitidos, podem prejudicar a saúde dos usuários e principalmente dos funcionários do estabelecimento. Para a realização da quantificação dos BTEX no ar, foi utilizada a técnica de amostragem ativa, seguida de extração por solvente e posterior análise por Cromatografia Gasosa com detecção por espectrometria de massas. O nível do ruído também foi um parâmetro estudado e comparado com a legislação vigente. Sabe-se que, principalmente em longo prazo, a exposição a níveis elevados de ruído prejudicam a audição e em alguns casos (normalmente os ocupacionais) sua perda total ou parcial. O equipamento utilizado para a medição foi um decibilímetro. Os resultados do kartódromo indoor, do outdoor e do estacionamento sem nenhuma atividade de kart foram analisados e comparados entre si
902

Visuomotor noise and the non-factive analysis of knowledge

Bricker, Adam Michael January 2018 (has links)
It is all but universally accepted in epistemology that knowledge is factive: S knows that p only if p. The purpose of this thesis is to present an argument against the factivity of knowledge and in doing so develop a non-factive approach to the analysis of knowledge. The argument against factivity presented here rests largely on empirical evidence, especially extant research into visuomotor noise, which suggests that the beliefs that guide everyday motor action are not strictly true. However, as we still want to attribute knowledge on the basis of successful motor action, I argue that the best option is to replace factivity with a weaker constraint on knowledge, one on which certain false beliefs might still be known. In defence of this point, I develop the non-factive analysis of knowledge, which demonstrates that a non-factive constraint might do the same theoretical work as factivity.
903

Effects of noise reduction on speech intelligibility / Les effets des réducteurs de bruit sur l’intelligibilité de la parole

Hilkhuysen, Gaston 22 September 2017 (has links)
On perçoit souvent la parole en présence de bien d’autres sons. Parfois les interférences sonores atteignent des niveaux tellement élevés que la parole devient inintelligible. Les méthodes de renforcement de la parole tentent de réduire les bruits ambiants, mais on en sait très peu sur l’effet qu’elles produisent sur l’intelligibilité de la parole. Cette thèse explore les effets des méthodes de renforcement de la parole, aussi appelées algorithmes de suppression du bruit, sur la l’intelligibilité.Après une brève introduction sur les notions de renforcement de la parole et d’intelligibilité, on présente trois études qui abordent les effets de ces méthodes d’un point de vue empirique. On démontre que le résultat de la suppression du bruit tend à réduire l’intelligibilité et que cet effet est constant pour une grande variété de niveaux sonores. Quand on fait appel à des experts pour mettre en place un système commercial de suppression du bruit dans le but d’améliorer l’intelligibilité, ils proposent des réglages qui dégradent l’intelligibilité. Les profanes perçoivent bien une amélioration de l’intelligibilité qui résulte des méthodes de renforcement de la parole.Trois autres études subséquentes tentent de préciser les propriétés du signal, qui ont des effets sur l’intelligibilité et qui sont généré par les méthodes de renforcement de la parole. Des métriques physiques basées sur différentes propriétés du signal ont été utilisées pour estimer l’intelligibilité de la parole renforcée. La plupart de ces mesures fournissent des estimations peu fiables ou biaisées de l’intelligibilité absolue. / Speech is often perceived in the presence of other sounds. At times the interfering sounds can reach such high levels that the speech becomes unintelligible. Speech enhancement methods attempt to reduce the audibility of noisy sounds, but little is known about how their influence on intelligibility. This thesis explores the effects of speech enhancement, also known as noise suppression algorithms, on speech intelligibility. After a short introduction to speech enhancement and intelligibility, three studies consider the effects from an empirical perspective. It is shown that noise suppression tends to reduce intelligibility and that its effect is mostly constant across a broad range of noise levels. When experts were asked to apply a commercial noise suppressor to optimise intelligibility, they proposed settings that degraded intelligibility. Laypeople successfully identified an increase in intelligibility resulting from speech enhancement. Three subsequent studies attempt to identify the signal properties responsible for the intelligibility effects and generated by speech enhancement.Physical metrics based on various signal properties were used to estimate the intelligibility of the speech-enhanced noisy signal. Most metrics provided unreliable or biased estimates of absolute intelligibility. Some could nevertheless be used to adjust speech enhancers such that intelligibility is optimal.
904

Urban morphology: from noise to joy.

January 2009 (has links)
Fok Lik Kan Duncan. / "Architecture Department, Chinese University of Hong Kong, Master of Architecture Programme 2008-2009, design report." / Includes bibliographical references.
905

Análise dos riscos físicos e ergonômicos em roçadora transversal motorizada /

Poletto Filho, José Antonio, 1959. January 2013 (has links)
Orientador: João Eduardo Guarnetti dos Santos / Banca: Kléber Pereira Lanças / Banca: Celso Luiz da Silva / Banca: José Angelo Cagnon / Banca: Jair Rosas da Silva / Resumo: No Brasil os números de acidentes no trabalho apresentaram uma redução de aproximadamente 7% entre os anos de 2008 e 2010, contudo, ainda são altos. Segundo Anuário Estatístico de Acidentes do Trabalho do Ministério do Trabalho e Emprego (2011) os números de acidentes de trabalho em 2006 foram 512.232, em 2007, 653.090, em 2008 755 mil, em 2009 733 mil e em 2010 um total de 701 mil, representando uma queda de aproximadamente 7 % no período. O presente trabalho teve por objetivo estudar os principais agentes geradores de lesões presentes na atividade dos operadores de roçadora transversal motorizada, que pode gerar sobrecargas físicas e mentais a estes operários. Os dados coletados a partir da percepção de uma amostra de quarenta e cinco trabalhadores na operação com este equipamento, que é cada vez mais utilizado nas operações de limpeza no meio rural e urbano, mostram riscos ao trabalhador em relação ao equipamento - calor, ruído e vibração -,às condições ambientais - trabalho a céu aberto - e à ergonomia - dores musculares. O trabalho em tela foi realizado na Rodovia Comandante João Ribeiro de Barros, em trecho de aproximadamente 100 quilômetros de extensão, entre os municípios de Bauru e Marília, na região oeste do Estado de São Paulo. Com relação aos resultados encontrados, o ruído ultrapassa 115 dB(A), vibração 4,0 m/s2 e estresse térmico de 29,9 0C. As avaliações ergonômicas também demonstraram que a atividade causa lesão aos trabalhadores. Diante disso, verificou-se a necessidade de serem propostas melhorias no equipamento e nas condições de trabalho.Para solucionar os altos níveis de ruído foi proposta a instalação de um silencioso na descarga dos gases gerados na combustão, fazendo com que o nível de ruído produzido pelo equipamento fosse reduzido, sendo assim, o protótipo aqui proposto reduziria ... / Abstract: In Brazil the numbers of accidents at work showed a reduction of about 7% between 2008 and 2010, still is high. According to Statistical Yearbook of industrial accidents of the Ministry of labor and employment (2011) the number of occupational accidents in 2006 were 512,232, in 2007, 653,090, 755 thousand were 2008, 2009 was seven hundred and thirty-three thousand and 2010 a total of seven hundred and one thousand, representing a decrease of approximately 7% over the period. The present work aimed to study the main generators of agents present in the lesions of motorized cross brush cutter operators that can generate physical and mental overloads to these workers. The data collected from the perception of a sample of 45 workers in operation with this equipment that is increasingly used in cleaning operations in urban and rural areas, show risks to workers in relation to equipment: heat, noise and vibration, in relation to environmental conditions: open-air and ergonomic work: muscle aches. The work was carried out in the screen Commander João Ribeiro de Barros Highway, approximately one hundred kilometers, between the municipalities of Bauru and Marília, in the Western region of the State of São Paulo in Brazil. With respect to results, the noise exceeds 115 dB (A) vibration and 4.0 m/s2. The ergonomic evaluations also demonstrated that the activity cause injury to employees. Given that, the need to propose improvements in the equipment and working conditions. To address the high levels of noise was proposed to install a silencer on the discharge of gases generated in combustion, thus causing the noise level produced by the equipment should be reduced, therefore the prototype proposed here would reduce the noise at approximately 107 dB (A). The vibration issue, for being an agent more complex,... / Doutor
906

An Integration Setup if the in-situ Mass and Spectroscopic Analysis for Volatile Liquids or Solids

Jones, Kolton K 01 April 2018 (has links)
To help address the growing need for more and better sensors, an attempt was made to produce an in-situ mass and spectroscopic analysis of liquid and solid samples, to characterize samples and sensors. Spectroscopic analysis consisted of Raman and FTIR where mass measurements were carried out. The sample or sensor’s holder would allow for spectroscopic analysis as well as expose the sample to high temperatures and various chemicals. While Raman and FTIR were successful in producing reliable and consistent data, the constructed watt balance was not. This failure was a result of eliminate vibrational noise.
907

Independent Acoustic Stimulation of the Amphibian and Basilar Papillae of Rana pipiens

Parker, Mark 07 July 1995 (has links)
This study attempted to selectively stimulate and record from either the amphibian or basilar papillae of Rana pipiens. Computer-generated, frequency-specific clicks were used to elicit BSER's from either amphibian or basilar papillae. Narrowband noise fatiguers were presented in the frequency region of which each papillae are tuned. It was expected that a threshold shift would be elicited in the papillae that received the acoustic trauma, and that no threshold shift would be observed from the collateral papilla. The results of this experiment indicated that there was no overall difference between the threshold shift of either papilla. Furthermore, the amount of AP threshold shift was relatively constant regardless of whether the fatiguer bandwidth was overloading the amphibian or basilar papillae. By contrast, the amount of BP threshold shift was greater when proceeded by a fatiguer with a bandwidth corresponding to the BP tuning region than by a fatiguer with a bandwidth corresponding to the AP tuning region. Additionally, curare maximized the amount of BP threshold shift following fatiguing noise presented with a bandwidth to which the AP is tuned.
908

Assessment of noise in a medical intensive care unit

Crawford, Kathryn J. 01 July 2016 (has links)
Exposure to noise in hospital intensive care units (ICUs) can disrupt patients’ sleep and delay their recovery. In this intervention study, noise levels were measured in eight patient rooms of a medical ICU (MICU) every minute with sound level meters for eight weeks before and after an intervention. Implemented over six weeks, the intervention was designed to educate nurses and other staff members to reduce noise levels through behavior modification, including instituting a “quiet time” in the afternoons, encouraging patients to keep televisions off or at lower volumes, and speaking more quietly during conversations. Sound equivalent levels (Leq) were calculated from one-minute measurements for each hour in each room. These hourly Leq (Leq-H) values were compared by pod (group of rooms within the MICU), room position (in proximity to a central nurses’ station), occupancy status, and time of day. Days with more than ten hours of one-minute noise levels above 60 dBA were flagged as the loudest time periods and compared to MICU activity logs. The intervention was ineffective with Leq-H values always above World Health Organization guidelines for ICUs (35 dBA in day; 30 dBA at night) before and after the intervention. Leq-H values frequently exceeded more modest project goals during the day regardless of the intervention (50% of Leq-H > 55 dBA both pre- and post-intervention) and at night (68% and 62% of Leq-H > 50 dBA pre- and post-intervention). Statistical analysis of the Leq-H suggests a general source is contributing to the high baseline noise in the MICU, most likely the heating, ventilation, and air-conditioning (HVAC) system. Our analysis of one-minute data indicated that high noise was often associated with high-volume respiratory-support devices. We concluded that our intervention focusing on administrative controls (e.g., education and training) was not enough to reduce noise in the MICU but that an intervention designed with engineering controls (e.g., shielding, substitution) would be more effective.
909

Occupational noise exposures of college town restaurant employees

Green, Deirdre Renee 01 July 2014 (has links)
Previous research evaluating restaurant worker exposure used environmental sound levels, but this does not take into account the temporal variability of restaurant worker exposure. To determine the actual personal exposure of restaurant workers, Quest Noise-Pro or Quest Edge dosimeters were placed on restaurant workers at six downtown Iowa City restaurants. At each participating locally-owned restaurant, workers classified as cooks, counter attendants, bartenders, and waiters participated. A time-weighted average (TWA) exposure per participant per shift was computed using both OSHA and NIOSH criteria for a total of 180 full-shift exposure measurements. Exposures were evaluated by season (when school is in session or not), restaurant type (counter service versus sit-down with bar), job title (cooks versus others), and time of week (weekday versus weekend) to characterize factors associated with high personal noise exposures. This work focused on day time exposures of restaurant employees in locally owned restaurants in a college town and determined the risks of noise induced hearing loss (NIHL). The results determined if restaurant workers are exposed to hazardous noise and whether exposures differ by job title, season, day of week and restaurant type. No TWA measurements exceeded the OSHA 8-hr TWA permissible exposure limit (PEL) of 90 dBA. Restaurant worker NIOSH TWAs ranged from 69-90 dBA with a mean (SD) of 80 dBA (4 dBA). Only 7.8% of all full-shift exposure data exceeded the NIOSH 8-hour 85 dBA. The highest worker TWAs were recorded during the period when the local university was in session and at the full-service restaurants: these workers were cooks during the weekends. Fourteen TWA measurements exceeded the NIOSH 8-hr TWA REL of 85 dBA. The NIOSH TWA exposure estimates significantly increased for full-service restaurants (p<0.001), cooks (p=0.003), during the fall semester (p=0.003), and during the weekend (p=0.048). Multiple Linear regression analysis suggested that restaurant type, job title, and season have a significant effect on restaurant worker noise exposures (p<0.001). Although restaurant employee noise exposures are within the OSHA hearing conservation standard limits, this study demonstrated that 7.8% (approximately 733,200) restaurant workers might be at risk for overexposure to noise based on NIOSH criteria. Intervention studies for the prevention of NIHL need to understand the impact of job title, restaurant type, season, and day of week on restaurant worker noise exposure. Additionally, all sampling was completed during the daytime and future research should evaluate restaurant worker noise exposures into the night time and early morning hours.
910

Subcoal seismic exploration in The Gippsland Basin (Australia)

Dunne, Jarrod C. Unknown Date (has links)
Deep seismic exploration in the Gippsland Basin is hindered by strong, unidentified noise below the Latrobe Group coal sequence. Low velocity events that appeared in field data semblance analyses suggested that an elastic wave modelling study was required to understand the subcoal reflection response. The modified reflectivity method (Kennet, 1980) provided a means for constructing detailed and accurate synthetic seismograms from realistic depth models, under the assumption of an isotropic, plane-layered earth. A study into the effect of each part of an elastic depth model (upon an elastic depth model (upon an elastic synthetic seismogram) resulted in a set of guidelines for obtaining a field data comparison. Excellent ties were obtained at several wells, often using little more than a partial sonic log. The noise contributions to the synthesis were interpreted using additional synthetics computed from variations upon the depth model and by exercising control over the wave types modelled. Subsequent processing of the synthetics revealed three types of persistent noise in progressively deeper parts of the subcoal image: 1) mode converted interbed multiples (generated within the coal sequence); 2) S-wave reflections and long period multiples (generated between the coal sequence and the Miocene carbonates and 3) surface related multiples.

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